Telemetric transmitter



Jan. 14, 1930.

K. MOEGER TELEMETRIC TRANSMITTER Filed April zo. 1927 PHoTo- ELec-rmc Cem..

Tnvewtor Kurt Moegev,

His Attoreg.

- operates with a scale a 35 indicated at 15.

Patented 14,130 y murs Astares 'mraa'rf zum? Menem. or Bamm, amm, Assrenrca To annulant.nnnrzfisnn: contraint.

"maaier l .A GOBPOBATION F NEW-YOBX l Tmnmnrmo TRANSMITTER.

Application filed April 20,1927, Serial Ho. 185,289, and in Germany November 5, 1926.

light on suchccell.

The features of my invention which are believed to be novel and patentable vwill be pointed out inthe claim appended hereto. For a better understanding of my invention reference is made to the following description'to the accompanying drawing in which Fig. 1 shows the essential parts of a telemetric system in which relatively rotatable Nicol prisms are employed in the transmitter; and

Fig. 2 shows a transmitter employing a movable graduated light screen.

Referring to Fig. 1, 10 represents an electric measuring instrument of the indlcatmg type. This device may obviously be any mov- 25 able indicating device, but I have represented a sensitive electrical measuring instrument because it is important that no .additional torque or friction be imposed on such instruments if they are to give accurate indications.

l1 represents the stationary field of the instrument, and 12 the rotatable armature. The armature is carried on a shaft 13 which also carries the usual pointer 14. The pointer coortion of wbichis It will e assumed that the angle of deflection extends over an aroof about 90 degrees.

The upper end of the shaft has an offset portion 16 extending around a stationary mirror 17. The mirror is set at a. suitable angle on the axis ofprotationof the instrument so as to reiect parallel light rays from a constant light source 18 and lens 19 upward along the axis of rotation. This beam of lightis 4.5 directed to a Nicol prism 20 which is supported by the upper end of the shaft part 16 also in the axis of' rotation of the instrument. Located above prism 20 is a second Nicol prism 21 which is stationary, and located abo-ve prism 21 is a photo-electric cell 22. The two prisms have their longitudinal axes in alinement on the axis of rotation of shaft 13 and also in alinementr'with the normff;

mal ath of the light rays directed from mirl ror 1 to the photo-electric cell 22. It is seen that as the instrument armature 12 moves through its angle of deflection the prism 2O is rotated through an angle of about degrees. The Nicol prisms as thus arranged..

have the power to radually. and uniformly intercept or cut oil a l the li ht reflected from mirror 17 to cell 22 as prism 2O is rotated through a 90 degree angle. The .prisms-are so posltioned with respect to each other that all the light is cut of at one end of the deiection angle and a maximum amount of light is allowed to pass at the other end of the deflection angle. As thus arranged the light falling on the photo-electric cell is radually and uniforml varied over the ection range of the instrument and noadditional -torque or friction is im osed on the`instrument. In the position s own themaximum amount of flight is allowed to pass through the prisms to thecell.

The photo-electric cell is contained in an electric circuit including a source of` voltage 24 where that is necessary or desirable. rllhe photo-electric cell produces a uniform variation in the current flowing in this circuit for uniform variations in the instrument deecl 23 such as a storage battery and an amplier`\- tion and such current after being amplified,

if' necessary, is caused to operate a receiving instrument 25 calibrated with the transmitting instrument.`

It will be apparent that this form of transmitter is also suitable forv sending impulses where the shaft rotates continuously as in a watthour meter.

In Fig. 2 I have represented a simplified transmitter where the two Nicol prisms are replaced by a graduated light screen in 'the form of a wedge-shaped circular member 26 which ma be made of a translucent material whichal ows practically no. light to pass through the thick end but asses practically all the light through the t in en It will be understood that in either modification suitable screens are to be provided for pre- 7;

.venting all light rays from strilrin the photoelectric cell except those coming t rough the transmitter system.

In accordance with the provisions of the patent statutes, I have described the rinciple of operation of my invention, toget er with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out hy other means.

What I claim as new and desire to secure l.

by Letters Patent of the United States, is

A telemeterinrr transmitter comprising a light source, a pi oto-electric cell, means for directing light from said source to sailcell, a pair of Nicol'prisrns having their longitudinal axes in alineinent with each other and in the normal path of the light rays directed fo said cell, a measuring instrument having a movable element, and means whereby the movement of said element causes the rotation 'of one of said'Nicol prisms with respect to the other aboutrits longitudinal axis, said :novement serving to vary the light falling upon said cell in proportion to the extent of such movement.

4 In witness whereof, I have hereunto set my hand this 1st day of April, 1927.

KURT MOEGER. 

